The next Democratic debate isn’t in Paterson, New Jersey, but it should be: that unlikely city is blazing new trails in multiculturalism and diversity. On Wednesday, the City Council voted unanimously (with two members not voting) to grant preliminary approval to the Islamic call to prayer being broadcast over loudspeakers in the city. This followed the swearing-in earlier this month, on the Qur’an, of course, of Paterson’s new police chief, Ibrahim “Mike” Baycora, the first Muslim police chief in an American city. Celebrate diversity, right? Sure. The problem is that it is by no means certain that this diversity will...